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一万年以来西安地区古土壤特征与气候波动变化研究 总被引：3，自引：0，他引：3
通过对西安李湾全新世黄土剖面微结构的研究,结合磁化率、TOC、CaCO3方法,发现古土壤S0是由两层土壤S10和S20构成的复合土壤,是森林植被下形成的具有强粘化和淋溶作用的棕壤类型.尽管有人类活动的影响,土壤S0以上部分仍继承了风积黄土的基本特征.初步揭示了关中地区一万年在6000-5000 aB.P. 出现的第一次干旱事件,3100年以来,是全新世以来又一个相对干旱的时期. 相似文献
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一万年以来西安地区古土壤特征及气候波动变化研究 总被引：3，自引：1，他引：3
通过对西安李湾全新世黄土剖面微结构的研究，结合磁化率，TOC，CaCO3方法，发现古土壤S0是由两层土壤S0^1和S0^2构成的复合土壤，是森林植被下形成的具有强粘化和淋溶作用的棕壤类型，尽管有人类活动的影响，土壤S0以上部分仍继承了风积黄土的基本特征，初步揭示了关中地区一万年在6000－5000aB.P，出现的第一次干旱事件，3100年以来，是全新世以来又一个相对干旱的时期。 相似文献
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冰期－间冰期旋回 总被引：1，自引：0，他引：1
王绍武 《气候变化研究进展》2008,4(1):61-62
第四纪(2.5 Ma BP)气候的一个重要特征就是冰期-间冰期旋回.目前我们正处于间冰期中,气候温暖.这个间冰期地质学家称为全新世,是从11.5 kaBP开始的,至今已延续了1万年以上.而在此之前是距我们最近的一次冰期,称为末次冰期. 相似文献
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利用植被与大气相互作用模式（AVIM）模拟了全新世中期（6 kaBP）及现代中国陆地植被净初级生产力（NPP）的大小与分布特征,计算了以上两个时期我国陆地植被NPP的碳总量。结果表明：全新世中期以来气候的变化是影响我国陆地植被NPP变化的主要原因,6 kaBP时期NPP平均值为409 g/（m2·a）, NPP碳总量为3.89 Pg/a,分别比现在高15%和19%。全新世中期至今,我国陆地植被NPP的变化特征与对应时期中国土壤碳储量的变化趋势具有很好的一致性,这表明了利用生态模式模拟长时间尺度下我国陆地植被NPP的变化特征是可行的。 相似文献
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MM5对中全新世时期中国地区气候的模拟研究 总被引：2，自引：1，他引：1
MM5模式结果与地质记录的对比表明,这个模式系统可以较好地模拟中全新世时气候的变化,特别是模式模拟的降水变化与地质记录吻合得较好.区域模式的结果比全球模式结果有所改进.模式结果显示:与现代相比,中全新世时,中国地区的气温升高,夏季升温超过冬季.同时,中国的内蒙古东部地区、东北地区和华北地区降水显著增加;而中国的华东、华中、华南和西南地区降水减少.中国东部30°N以北地区夏季风增强;中国东部的冬季风减弱.从一系列敏感试验结果,可以发现:在中全新世时,中国地区的气温、风场和降水的变化主要受大尺度环流背景场变化的影响,其对降水变化的影响超过50%.其次受地表状况和植被变化的影响,植被的变化主要影响中国东部地区,使得在冬季和夏季中国地区均升温;而且,对华北部分地区降水变化的影响最大超过25%.地球轨道的变化使得中全新世时太阳辐射的季节变化较大,造成中全新世时中国地区在冬季降温,在夏季升温;同时,对东北和华北地区的降水有重要影响,其影响与植被变化的影响相当.中全新世时,大气中CO2的体积混合比为280×10-6,CO2的变化使得中伞新世时气温降低,但量级较小.影响中全新世时中国地区气候变化的因子,按影响程度由大到小的排序为:大尺度环流背景场、植被变化、地球轨道参数变化和CO2浓度变化. 相似文献
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根据当前国内的研究成果,总结了地质时期第四纪(距今250多万a)以来黄土高原演变与气候变迁之间的关系,其主要关系可归纳为:①第三纪以来喜马拉雅造山运动引起的中国大陆一系列差异性升降构造变化是黄土高原形成的决定性因素;②更新世时期青藏高原隆起所引起的强西风气流把中亚内陆沙漠地区的大量粉尘带到今天的黄土高原地区,形成了黄土高原;③现代季风是更新世时期青藏高原上升到某个高度之后的产物,但随着青藏高原高度不断增长,它对湿润夏季风的屏障作用越来越强,黄土高原气候开始由温暖湿润向干冷和干旱化方向发展,相应地植被种类和分布发生调整;④黄土高原植被对气候波动的适应具有重复性,即植物随着气候冷暖干湿的波动,生长区域南北移动;⑤黄土高原水土流失在更新世时期主要是自然侵蚀造成的,全新世时期在遵循自然规律继续进行的基础上,又叠加了人类活动影响,使之呈现加速发展的特点;⑥黄土高原水土流失受地质、降水、植被与人类活动等多种因素的影响,空间差异极其显著。 相似文献
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活动层水热状况与地-气系统间能水交换直接影响着寒区生态环境、水文过程以及多年冻土的稳定性。利用唐古拉站2007年实测资料和SHAW模型,对研究点活动层土壤剖面温湿度进行了模拟。土壤温度方面,模型的纳什效率系数NSE≥0.93;水分方面,纳什效率系数的平均值为0.69,说明SHAW模型可用于多年冻土区活动层内水热动态变化的模拟研究。基于模型的输出结果,对唐古拉站活动层土壤冻融过程中的水分动态、地表能量收支的变化特征进行了分析讨论。结果表明:(1)活动层冻融过程中,土壤水分的冻结和融化响应时间随土壤深度的增加而逐渐滞后,水分迁移通量随土壤深度的增加逐渐减小;(2)地表能量平衡收支在季风活动引起的降水与活动层的冻融循环共同影响下,表现出明显的季节性变化特征。同时,通过改变SHAW模型植被输入参数中的叶面积指数,分析了植被覆盖变化对多年冻土区土壤蒸散发的影响。结果表明:植被蒸腾量、土壤蒸发量与总的蒸散发量与植被的叶面积指数呈正相关关系,而浅层土壤含水率(20 cm)则表现为负相关,当叶面积指数在-100%(裸土)~100%变化时,总蒸散发量的变化幅度为-5%~13%。 相似文献
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刘兴诗 《高原山地气象研究》2007,27(1)
当前沙尘暴活动愈益受到人们关注,或以为其是近期以来人为破坏荒漠植被的结果.分析第四纪黄土生成历史,以及历史时期大量雨土记录可见,其实沙尘暴古已有之,古时活动剧烈程度较今日有过之无不及.黄土堆积乃沙尘暴的直接产物,雨土是其过程和现象.第四纪冰期结束以来的全新世期间,存在2500-3000年的冷暖干湿变化周期.经历了大约2500年的亚大西洋期行将结束,新的灾变时期即将来临.在此总的大自然气候发展背景下,沙尘暴活动加强是不可避免的,人为活动并非主要因素,只不过加剧其程度而已. 相似文献
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利用国际古气候模拟对比计划第四阶段的多模式结果,分析了末次间冰期亚洲中部干旱区的干湿变化及机制。多模式集合平均结果表明,末次间冰期亚洲中部干旱区年降水减少0.7％,其中中亚地区的年降水减少2.8％,新疆地区年降水增加1.8％。水汽收支方程表明,末次间冰期中亚地区在雨季（冬春季）的降水变化主要与垂直动力项有关,新疆地区在雨季（夏季）的降水变化主要与垂直动力与热力项有关。此外,基于Penman-Montieth方法计算的亚洲中部干旱区的干旱指数在末次间冰期减小约10.2％,表明末次间冰期亚洲中部干旱区气候明显变干且存在旱区扩张的现象,这主要受到潜在蒸散变化的调控。潜在蒸散的增加进一步受到有效能量增加与地面风速增大的调控。本研究从模拟的角度揭示了末次间冰期亚洲中部干旱区干湿变化的可能特征及机制,在一定程度上有助于理解旱区气候在增暖情景下对轨道参数的响应特征。 相似文献
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The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics. 相似文献
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Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d. 相似文献
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Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region. 相似文献
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Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms. 相似文献
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Yuepeng PAN Mengna GU Yuexin HE Dianming WU Chunyan LIU Linlin SONG Shili TIAN Xuemei Lü Yang SUN Tao SONG Wendell W. WALTERS Xuejun LIU Nicholas A. MARTIN Qianqian ZHANG Yunting FANG Valerio FERRACCI Yuesi WANG 《大气科学进展》2020,37(9):933-938
正While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-term surface observation of ammonia concentrations are sparse. In addition, there is still no consensus on 相似文献
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《大气和海洋科学快报》2013,(1):67
正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome.SUBMISSIONAll submitted 相似文献
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<正>With the support of specialized funds for national science institutions,the Guangzhou Institute of Tropical and Marine Meteorology,China Meteorological Administration set up in October 2008 an experiment base for marine meteorology and a number of observation systems for the coastal boundary layer,air-sea flux,marine environmental elements,and basic meteorological elements at Bohe town,Maoming city,Guangdong province,in the northern part of the South China Sea. 相似文献
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《大气和海洋科学快报》2014,7(6):F0003-F0003
AIMS AND SCOPE
Atmospheric and Oceanic Science Letters （AOSL） publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献
Atmospheric and Oceanic Science Letters （AOSL） publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献
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《大气和海洋科学快报》2014,(5):F0003-F0003
AIMS AND SCOPE Atmospheric and Oceanic Science Letters （AOSL） pub- lishes short research letters on all disciplines of the atmos- phere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献